repo: rework parser setup to handle `init -c`

We added support for `repo init -c` to main.py, but not to the
launcher, so the -c option only works after the first init has
run which kind of defeats its purpose.  Rework the parser setup
so that we can tell it whether it's for "init" or "gitc-init"
and then add the -c option in the same way we do in main.py.

This has the benefit of getting the parser entirely out of the
module scope which makes it a lot easier to reason about, and
it means we can write some unittests.

Change-Id: Icbc2ec3aceb938d5a8f941d5fbce1548553dc5f7
Test: repo help init
Test: repo help gitc-init
Test: repo init -u https://android.googlesource.com/platform/manifest -c
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/255113
Reviewed-by: David Pursehouse <dpursehouse@collab.net>
Tested-by: Mike Frysinger <vapier@google.com>
diff --git a/repo b/repo
index f7e7581..5674be8 100755
--- a/repo
+++ b/repo
@@ -253,26 +253,37 @@
 gpg_dir = os.path.join(home_dot_repo, 'gnupg')
 
 extra_args = []
-init_optparse = optparse.OptionParser(usage="repo init -u url [options]")
 
 
-def _InitParser():
-  """Setup the init subcommand parser."""
+def GetParser(gitc_init=False):
+  """Setup the CLI parser."""
+  if gitc_init:
+    usage = 'repo gitc-init -u url -c client [options]'
+  else:
+    usage = 'repo init -u url [options]'
+
+  parser = optparse.OptionParser(usage=usage)
+
   # Logging.
-  group = init_optparse.add_option_group('Logging options')
+  group = parser.add_option_group('Logging options')
   group.add_option('-q', '--quiet',
                    action='store_true', default=False,
                    help='be quiet')
 
   # Manifest.
-  group = init_optparse.add_option_group('Manifest options')
+  group = parser.add_option_group('Manifest options')
   group.add_option('-u', '--manifest-url',
                    help='manifest repository location', metavar='URL')
   group.add_option('-b', '--manifest-branch',
                    help='manifest branch or revision', metavar='REVISION')
   group.add_option('-m', '--manifest-name',
                    help='initial manifest file', metavar='NAME.xml')
-  group.add_option('--current-branch',
+  cbr_opts = ['--current-branch']
+  # The gitc-init subcommand allocates -c itself, but a lot of init users
+  # want -c, so try to satisfy both as best we can.
+  if not gitc_init:
+    cbr_opts += ['-c']
+  group.add_option(*cbr_opts,
                    dest='current_branch_only', action='store_true',
                    help='fetch only current manifest branch from server')
   group.add_option('--mirror', action='store_true',
@@ -310,7 +321,7 @@
                    help="don't fetch tags in the manifest")
 
   # Tool.
-  group = init_optparse.add_option_group('repo Version options')
+  group = parser.add_option_group('repo Version options')
   group.add_option('--repo-url', metavar='URL',
                    help='repo repository location ($REPO_URL)')
   group.add_option('--repo-branch', metavar='REVISION',
@@ -319,21 +330,20 @@
                    help='do not verify repo source code')
 
   # Other.
-  group = init_optparse.add_option_group('Other options')
+  group = parser.add_option_group('Other options')
   group.add_option('--config-name',
                    action='store_true', default=False,
                    help='Always prompt for name/e-mail')
 
+  # gitc-init specific settings.
+  if gitc_init:
+    group = parser.add_option_group('GITC options')
+    group.add_option('-f', '--manifest-file',
+                     help='Optional manifest file to use for this GITC client.')
+    group.add_option('-c', '--gitc-client',
+                     help='Name of the gitc_client instance to create or modify.')
 
-def _GitcInitOptions(init_optparse_arg):
-  init_optparse_arg.set_usage("repo gitc-init -u url -c client [options]")
-  g = init_optparse_arg.add_option_group('GITC options')
-  g.add_option('-f', '--manifest-file',
-               dest='manifest_file',
-               help='Optional manifest file to use for this GITC client.')
-  g.add_option('-c', '--gitc-client',
-               dest='gitc_client',
-               help='The name of the gitc_client instance to create or modify.')
+  return parser
 
 
 # This is a poor replacement for subprocess.run until we require Python 3.6+.
@@ -432,11 +442,10 @@
 def _Init(args, gitc_init=False):
   """Installs repo by cloning it over the network.
   """
-  if gitc_init:
-    _GitcInitOptions(init_optparse)
-  opt, args = init_optparse.parse_args(args)
+  parser = GetParser(gitc_init=gitc_init)
+  opt, args = parser.parse_args(args)
   if args:
-    init_optparse.print_usage()
+    parser.print_usage()
     sys.exit(1)
 
   url = opt.repo_url
@@ -896,12 +905,9 @@
 
 def _Help(args):
   if args:
-    if args[0] == 'init':
-      init_optparse.print_help()
-      sys.exit(0)
-    elif args[0] == 'gitc-init':
-      _GitcInitOptions(init_optparse)
-      init_optparse.print_help()
+    if args[0] in {'init', 'gitc-init'}:
+      parser = GetParser(gitc_init=args[0] == 'gitc-init')
+      parser.print_help()
       sys.exit(0)
     else:
       print("error: '%s' is not a bootstrap command.\n"
@@ -983,7 +989,6 @@
           'command from the corresponding client under /gitc/',
           file=sys.stderr)
     sys.exit(1)
-  _InitParser()
   if not repo_main:
     if opt.help:
       _Usage()
diff --git a/tests/test_wrapper.py b/tests/test_wrapper.py
index 4d2cf3f..a98c413 100644
--- a/tests/test_wrapper.py
+++ b/tests/test_wrapper.py
@@ -66,6 +66,20 @@
     self.assertEqual('', stderr.getvalue())
     self.assertIn('repo launcher version', stdout.getvalue())
 
+  def test_init_parser(self):
+    """Make sure 'init' GetParser works."""
+    parser = self.wrapper.GetParser(gitc_init=False)
+    opts, args = parser.parse_args([])
+    self.assertEqual([], args)
+    self.assertIsNone(opts.manifest_url)
+
+  def test_gitc_init_parser(self):
+    """Make sure 'gitc-init' GetParser works."""
+    parser = self.wrapper.GetParser(gitc_init=True)
+    opts, args = parser.parse_args([])
+    self.assertEqual([], args)
+    self.assertIsNone(opts.manifest_file)
+
   def test_get_gitc_manifest_dir_no_gitc(self):
     """
     Test reading a missing gitc config file